Railway signaling



July 19, 1938. R. ALLISON 2,123,922

RAILWAY SIGNALING FiledMarch 14, 1936 -9 Sheets-Sheet l INVENTOR Les liwllison.

1X55 ATTORNEY July 19, 1938. R. ALLISO N 2,123,922

RAILWAY SIGNALING Filed March 14, 1956 e Sheets-Sheet 2 INVENTOR Leslie .Allz lson.

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HIS ATTORNEY July 19, 1938.

L. R. ALLISON RAILWAY SIGNALING Filed March 14, 1936 9 Sheets-Sheet 3 INVENTOR Leslie llzson.

HIS ATTORNEY July 19, 1938. L. R. ALLISON RAILWAY SIGNALING Filed March 14, 1936 e Sheets-Sheet 4 n v M RN m mu m T N NA R E o w w a s w m H NQN w A u. 3 n fl E- F 5w n u. 59 A wfi m mm mw mm fig NEW 5 b w h E w m @w f: r

July 19, 1938. R, sg 2,123,922

RAILWAY SIGNALING Y Filedjlrch 14, 1936 .9 Sheets-Sheet 5 INVE TOR N HIS ATTORN EY July 19, 1938. R. ALLISON 2,123,922

RAILWAY SIGNALING Filed March 14, 1956 '9 Sheets-Sheet e INVENTOR B. 1 Leslie Allison. :r -\:l 23 2 BY H18 ATTORNEY July 19, 1638. L, R LI N; I 2,123,922

RAILWAY S IGNALING Filed March 14, 1956 9 Sheets-Sheet 7 Fig. 7.

i INVENTOR Leslie Allison.

HIS ATTORNEY July 19, 1938. 1.. R. ALLISON RAILWAY SIGNALING Filed March 14,. 1936 9 Sheets-Sheet 8 mvEN-roR L eslie Allison.

HIS ATTORNEY July 19, 1938, R ALLISON 2,123,922

RAILWAY SIGNALING Filed March 14, 1956 e Sheets-Sheet 9 INVVENTOR .Allzlson. BY 5 2 m5 ATTORNEY Patented July 19, 1938 UNITED STATES PATENT OFFl-CE RAILWAY SIGNALING Application March 14, 1936, Serial No. 68,807

27 Claims.

My invention relates to railway signaling, and particularly to signaling involving wayside signals located along a trackway for governing the passage of trains.

A feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each of four track sections in the rear of an occupied section. Each distinctive control is effective to cause a corresponding aspect of the associated wayside-signal, whereby there is produced a four-block, five-indication system of signaling.

Another feature of my invention is the provision of novel and improved apparatus for establishing a distinctive control for each of three track sections in rear of an occupied section for controlling the associated wayside signal to produce a three-block, four-indication signaling system.

The system shown in this application is an improvement on the systems shown in an application of Howard A. Thompson, Serial No. 692,155, filed October 4, 1933, for Railway trafiic controlling apparatus; in an application of Henry S. Young, Serial No. 66,002, filed February 2'7, 1936, for Railway signaling; in United States Patent No. 2,062,055, issued November 24, 1936, to Ralph R. Kemmerer, for Railway signaling; in an application of George R. Pflasterer, Serial No. 68,497, filed March 12, 1936, for Railway signaling; and in an application of Paul H. Crago, Serial No. 631,041, filed August 30, 1932, for Remote control systems.

I will describe several forms of apparatus em- 35 bodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawings, Figs. 1A, 1B, and 1C are diagrammatic views which, when placed end to end in the order named, illustrate one form of four-block, five-indication, signaling system embodying my invention. Figs. 2A and 2B are diagrammatic views which, when placed end to end in the order named, illustrate one form of three-block, four-indication signaling system embodying my invention. Figs. 3, 4, 5, 6, 7, and 8 are diagrammatic views illustrating modifications of a portion of the apparatus shown in Figs. 2A and 2B, and each also 'embodies my invention. Fig. 9 is a diagrammatic view illustrating a modification of a portion of the apparatus shown in Fig. 8 and also embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1A, 1B, and 10, the reference characters l5 and I6 designate the rails of a stretch of railway track along which trafiic normally moves in the direction indicated by the arrows. The rails l5 and I6 are divided by insulated joints I 1 into track sections V-W, WX, XY, and YZ. Each track section is divided into at least two subsections IT, 2T, 3T, 4T, etc.

Each subsection is provided with a track battery l8 connected across the rails at one end of the subsection and with a track relay, designated by the reference character TR with a prefix the same as the numerical prefix of the associated subsection, connected across the rails at the other end of the subsection.

For governing the passage of trains along the stretch, each track section is provided with a wayside signal designated by a suitable distinguishing reference character.

These signals may take any one of several forms such as searchlight, color light, semaphore, or position light. As here shown, each signal is of the color light type and includes an upper indication unit U and a lower indication unit L. Each unit U and each unit L includes a red lamp R and a yellow lamp Y as well as a green lamp G.

For controlling the signals, each section is provided with a polarized direct current relay and with a neutral direct current relay designated by the reference characters H and J, respectively, each with a prefix the same as the reference character of the associated signal.

For controlling the relays, H and J, each section is provided with a line circuit which includes a pair of line wires each of which includes a front contact of each of the associated track relays. As will be explained more in detail hereinafter, the line circuits, at times, are supplied with direct current only of one polarity or the other and at other times are supplied with alternating current simultaneously with direct cur-- rent.

Each polarized relay H is directly connected to the associated line circuit. Each neutral relay J is connected tothe associated line circuit through an asymmetric unit, a transformer, and a condenser designated by the reference characters Q, M, and F, respectively, each with a prefix the same as the referencecharacter of the associated signal. The relatively high impedance of the windings of the relays H will prevent the fiow of alternating current in these relays and the condensers F, together with the transformers M will prevent the flow of the direct current from the line circuit in the windings of the relays J. The relays H, therefore, respond to direct current in the line circuits and the relays J respond to alternating current in the line circuits.

Each section is provided with a suitable source of direct current here shown as a battery 9 with its terminals designated by the reference characters B and C.

Each section is provided with a transformer designated by the reference character N with a prefix the same as the reference character of the associated signal and having a primary winding l9 and a secondary winding 25) which is connected in series with the associated battery 9.

For supplying alternating current to the transformers N, each section is provided with a device, designated by the reference character A with a prefix the same as the reference character of the associated signal, for converting direct current into alternating current. As here shown, each device A is an alternator of the well-known tuned reed type. Referring to the alternator |0A, for example, the reference character 2| designates a reed which is caused to vibrate between terminals 22 and 23 by a control winding 24. In the deenergized condition, reed 2| does not connect with either terminal 22 or terminal 23 but does connect with a terminal 25. When energy is supplied to the alternator ltA, winding 24 will attract reed 2| causing it to connect with terminal 22 and to move away from terminal 25, causing winding 24 to become deenergized. Upon the deenergization of winding 24, the resilience of reed 2| will cause it to move away from terminal 22 and to connect with terminal 23 as well as with terminal 25. The circuit for winding 24 will then be completed so that reed 2| again will go through the cycle of operation just described. Winding 24, therefore, will be repeatedly energized and deenergized as long as energy is supplied to its control circuit. When reed 2| connects with terminal 23, current is then supplied to the right-hand portion of primary winding IQ of transformer UN; and when reed 2| connects with terminal 22, current is supplied in the opposite direction to the left-hand portion of primary winding l9. Alternating current, therefore, will be induced in the secondary winding 20 of transformer ION.

Energy is supplied to operating winding 24 of alternator IBA whenever the relay IBH is energized in the reverse direction provided the relay IOJ is then deenergized, or whenever the relay ill-I is energized in the normal direction.

The alternators A for each of the other sections are controlled by the associated relays H and J and function to supply alternating current to the associated transformer N in a manner identical to that described for alternator WA.

For controlling the polarity of the direct current supplied to the line circuit for the section next in rear, each section is provided with a slow releasing relay designated by the reference character HP with a prefix the same as the reference character of the associated signal. Each relay HP is controlled by the associated relays H and J in such a manner that the relay HP is energized whenever the relay J is energized or Whenever the relay H is energized in the normal direction provided the relay J is then deenergized.

The lamps of the indication units U and L of the signals are controlled by the relays H and J in the following manner: When relay H is deenergized (see signal 54), the red lamp R. of the upper unit U of that signal is energized by a cir cuit which passes from terminal B through back point of contact 26 of relay MH and lamp R to terminal C; and the red lamp R of the lower unit L of that signal is energized by a circuit which passes from terminal B through back point of contact 21 of relay MH and lamp R, to terminal C, so that signal i4 displays a red light above a red light to indicate stop. When relay H is energized in the reverse direction and relay J is deenergized (see signal |3) the yellow lamp Y of the upper unit U of that signal is energized by a circuit which passes from terminal B through front point of contact 28 of relay |3H, normal polar contact 2930 of relay |3H, and lamp Y to' terminal C; and the red lamp R of the lower unit L of that signal is energized by a circuit which passes from terminal B through front point of contact 3| and reverse polar contact 32-33 both of relay |3H, back contact 34 of relay |2J, and lamp R to terminal C, so that signal |3 displays a yellow light above a yellow light to indicate approach next signal prepared to stop. When relay H is energized in the reverse direction and relay J is energized (see signal l2) the yellow lamp Y of the upper unit U of that signal is energized by a circuit which passes from terminal B through front point of contact 35 of relay |2H, reverse polar contact 29-3i1 of relay |2H, and lamp Y to terminal C; and lamp Y of the lower unit L of that signal is energized by a circuit which passes over the same path as just described for the yellow lamp of the upper unit including reverse polar contact 2939 of relay IZI-I, and thence over front point of contact 35 of relay J and lamp Y to terminal C, so that signal |2 displays a yellow light above a yellow light to indicate proceed at medium speed. When relay H is energized in the normal direction and relay J is deenergized (see signal II), the green lamp G of the upper unit U of that signal is energized over a circuit Which passes from terminal B through front point of contact 31 of relay ||H, normal polar contact 29-38 of relay HH, and lamp G to terminal C; and lamp Y of the lower unit L of that signal is energized over the same circuit as just traced for lamp G up to and including normal polar contact 29-38 of relay ll-I, and thence over back point of contact 39 of relay |J to lamp Y and terminal C, so that signal displays a green light above a yellow light to indicate approach next signal at medium speed. When relay H is energized in the normal direction and relay J also is energized (see signal Hi), the green lamp G of the upper unit U of that signal is energized over a circuit which passes from terminal B through front point of contact 40 of relay IUH, normal polar contact 2938 of relay IUH, and lamp G to terminal C; and the green lamp G of the lower unit L of that signal is energized over the same circuit as just traced for the green lamp of the upper unit, up to and including normal polar contact 2938 of relay NIH, and thence over front point of contact 4| of relay IUJ to lamp G and terminal C, so that signal l0 displays a green light above a green light to indicate proceed at normal speed.

As shown in the drawings, a train K occupies the section immediately to the right of location Z so that the line circuit for the control of relays |4H and |4J is opened. When both relays M l-I and |4J are deenergized, relay |4HP is deenergized so that relay |3H is supplied with direct current of reverse polarity over a circuit which passes from terminal B of battery 9 at signal 14, through back point of contact 42 of relay .liI-IP, frontcontact43 of relay 8TB, front.

contact 44 of relay lTR, relay [3H, front contact 45 of relay .TTR, front contact 46 of relay 8TB, back point of contact '41 of relay MHP, and secondary winding 20 of transformer MN to terminal C.

When relay i3I-I is energized in the reverse direction and relay I3J is deenergized, relay I3HP remains deenergized but alternator I3A is energized over a circuit which passes from terminal B through backpoint of contact 48 of relay ISJ, front contact 49 and reverse polar contact 505l both 'of relay I3H and winding 24 toterminal C. When relay I3HP is deenergized and alternator 13A is operating, relay IZH is energized in the reverse direction over a circuit which-passes from terminal B of battery 9 at signal l3, through back point of contact 52 of relay I3HP, front contact 53 of relay 6TB, front contact 54 of relay 5TR, relay l2H, front contact 55 of relay 5TB, front contact 55 of relay 6TB, back point of contact 5'! of relay IBHP, and secondary winding 26 of transformer l3N to ter minal C; and primary winding 58 of transformer 12M is energized by alternating current over the same circuit as just described for relay IZH, except including condenser HF and primary winding 58 of transformer 42M instead of relay 12H. When primary winding .58 is energized, current is induced in secondary winding 59 of transformer HM so that relay IZJ is energized by direct current through asymmetric unit IZQ.

When relay HE is energized in the reverse direction and relay |2J also is energized, relay IZHP is energized over front point of contact 69 of relay lZJ but alternator HA is deener gized. When relay IZHP is energized and alternator 12A is deenergized, relay l IE is supplied with direct current in the normal direction over a circuit which passes from terminal B of battery 9 at signal I2, through front point of contact 6| of relay lZI-IP, front contact 62 of relay 4TB, front contact 63 of relay 3TB, relay Ill-I, front contact 64 of relay 3TB, front contact 65 of relay 4TB, front point of contact 66 of relay IZHP, and secondary winding 20 of transformer l2N to terminal C.

When relay III-I is energized in the normal direction and relay IIJ is deenergized, relay IIHP is energized over a circuit which passes from terminal B through back point of contact 61 of relay IIJ, front contact 68 of relay IIH, normal polar contact 5069 of relay HH, and relay HP to terminal C; and alternator HA is energized over a circuit which passes from terminal B through front contact 10 of relay HH, normal polar contact ll-l2 of relay HH, and winding 24 of alternator A to terminal C.

When relay HHP is energized and alternator HA is energized, relay NIH is energized in the normal direction over a circuit which passes from terminal B of battery 9 at signal I I, through front point of contact 13 of relay HHP, front contact 14 of relay ZTR, front contact 15 of relay ITR, relay IOHT, front contact 76 of relay ITR, front contact 11 of relay 2TR, front point of contact 18 of relay l lI-lIP, and secondary winding 26 of transformer N to terminal 0; and primary winding 58 of transformer IBM is energized by alternating current over the same path as just described for relay lllI-I, except substituting condenser 10F and primary winding 58 for relay IOI-I. When primary winding 58 is energized by alternating current, secondary winding 59 of transformer IUM is energized .so that relay NJ is energized .by direct current through asymmetric unit IOQ.

When relay lllI-I is energized in the normal direction and relay lllJ .also is energized, relay HlHP and alternator lllA both-are energized over easily traced circuits so that the line circuit for the section immediately :in the rear of location V is supplied with .alternating current as well as with direct current of normal polarity.

Summing up thus far, each signal is controlled by a polarized direct current line relay and by a neutral direct current line relay. The polarized relay is directly connected to a twowire line circuit and the neutral relay is connected to the line circuit through an asymmetric unit and a transformer. The line circuit for energizing the polarized and neutral relays associated with the signal for each section is governed by each of the track relays for that section and by the polarized and neutral relays for the signal next in advance.

When both line relays are deenergized, the associated signal will indicate stop and the line circuit to the rear will be supplied with direct current only of reverse polarity. When the polarized relay alone is energized in the reverse direction, the associated signal will indicate prepare to stop at next signal, and the line circuit in the rear will be supplied with direct current of reverse polarity simultaneously with alternating current. When the polarized relay is energized in the reverse direction and the neutral relay also is energized, the associated signal will indicate proceed at medium speed and the line circuit to the rear will be supplied with direct current only in the normal direction. When the polarized relay alone is energized in the normal direction, the associated signal will indicate approach next signal at medium speed and the line circuit to the rear will be supplied with alternating current simultaneously with direct current of normal polarity. When the polarized relay is energized in the normal direction and the neutral relay also is energized, the associated signal will indicate proceed at normal speed and the line circuit to the rear will be supplied with alternating current simultaneously with direct current in the normal direction.

It will be noted that the relays HP have a slowreleasing characteristic. This feature is provided in order to insure that the energization of the line circuits to the rear will not be disturbed during pole-changing periods. For example, when the train K passes out of the section immediately to the right of location Z, relay I 2H will be supplied with energy in the normal direction and relay l 2J will become deenergized so that signal l2 will indicate approach next signal at medium speed instead of its present indication of proceed at medium speed. When this occurs, the control circuit for relay I2HP will become momentarily opened at front point of contact 60 of relay IZJ until such time as front contact 68 and normal polar contact 5069 of relay 12H can become closed. Relay .IZI-IP, however, will not open the front-points of its contacts 6| and 66 so that energization of relay l iH is not disturbed.

Referring next to Figs. 2A and 2B, the system illustrated herein is a three-block, four-indication, signaling system.

Each signal includes an upper unit U comprising a red and ayellow as well as-a green lamp, and a lower unit LB comprisingv a red and a yellow lamp.

Each section isprovided withthe'usual signal control relays H and J which are connected to the associated line circuit in a manner similar to that described for the apparatus shown in Figs. 1A, 1B, and 10.

Each section is provided with the battery 9 and with the transformer N as well as with the alternator A.

The relays HP are controlled in the usual manner by the associated relays H and J.

The line circuits for the sections next in rear are governed by the relays HP and the alternators A are governed by the relays H and J.

The relays H and J govern the signals in the following mannerrWhen both relays H and J are deenergized (see signal I3) the red lamp R of the upper unit U of that signal is energized over a circuit which passes from terminal B through back point of contact I9 of relay I3H and lamp R to terminal C; and red lamp R of the lower unit LB of that signal is energized over a circuit which passes from terminal B through back contact of relay ISJ and lamp R to terminal C, so that signal 53 displays a red light above a red light to indicate stop. When relay H is energized in the reverse direction and relay J is deenergized (see signal I2), a yellow lamp Y of the upper unit U of that signal is energized over a circuit which passes from terminal B through front point of contact 8! of relay IZI-I, reverse polar contact 82-433 of relay IZI-I, and lamp Y to terminal C; and red lamp R of the lower unit LB of that signal is energized over a circuit which passes from terminal B through back contact 84 of relay I2J and lamp R to terminal C, so that signal I2 displays a yellow light above a red light to indicate approach next signal prepared to stop. When relay H is energized in the reverse direction and relay J also is energized (see signal I I), the yellow lamp Y of the upper unit U of that signal is energized over a circuit which passes from terminal B through front point of contact 85 of relay IIH, reverse polar contact 8283 of relay I IE, and lamp Y to terminal C; and yellow lamp Y of the lower unit LB of that signal is energized over a circuit which follows the same path as just described for lamp Y of the upper unit, up to and including reverse polar contact 8283, and thence through front contact '86 of relay IIJ and lamp Y to terminal C, so that signal II displays a yellow light above a yellow light to indicate approach next signal at medium speed. When relay H is energized in the normal direction and relay J is deenergized (see signal I0), green lamp G of the upper unit U of that signal is energized over a circuit which passes from terminal B through front point of contact 81 of relay IOH, normal polar contact 8288 of relay IflH, and lamp G to terminal C; and red lamp R of the lower unit LB of that signal is energized over a circuit which passes from terminal B through back contact 89 of relay NIH and lamp R to terminal C; so that signal It displays a green light above a red light to indicate proceed at normal speed.

As shown in the drawings, the train K occupies the section immediately to the right of location Y so the line circuit for energizing relays I3H and ISJ is opened. Consequently, both these relays are deenergized so that relay I3HP also is deenergized. When relay HE)? is deenergized, relay I2H is energized in the reverse direction over a circuit which passes from terminal B of battery 9 at signal I3, through secondary winding 20 of transformer I3N, back point of contact 9| of relay I3HP, front contact 92 of relay BTR, front contact 93 of relay 5TB, relay I 2H, front contact 94 of relay 5TB, front contact 95 of relay 6TB, and back point of contact 96 of relay I3HP to terminal C of battery 9 at signal I3.

When relay I2H is energized in the reverse direction and relay IZJ is deenergized, relay IZI-l]? remains deenergized but alternator I2A is energized over a circuit which passes from terminal B through back point of contact 91 of relay I2J, front contact 98 of relay IZH, reverse polar contact 99I90 of relay I2I-I, and alternator I2A to terminal 0.

When relay I 2HP is deenergized and alternator I2A is energized, relay I IH is energized in the reverse direction over a circuit which passes from terminal B of battery 9 at signal I2, through sec ondary winding 29 of transformer I 2N, back point of contact IOI of relay IZHP, front contact I02 of relay 4TB, front contact I93 of relay 3TB, relay I IH, front contact I04 of relay 3TB, front contact I95 of relay 4TB, and back point of contact I96 of relay IZHP to terminal C, and primary winding 58 of transformer I IM is energized simultaneously with alternating current over the same circuit just traced for relay I II-I, except that condenser I IF and primary winding 58 should be substituted for relay I IH. When primary winding 58 is energized, current is induced in secondary winding 59 so that relay I IJ is energized by direct current through asymmetric unit I IQ.

When relay I IH is energized in the reverse direction and relay I IJ also is energized, alternator HA is deenergized and relay III-1P is energized over a circuit which passes from terminal B through front point of contact I91 of relay I IJ and relay I IHP to terminal C.

When relay III-LP is energized, relay NIH is energized in the normal direction over a circuit which passes from terminal B of battery 9 at signal II, through front point of contact I08 of relay III-1P, front contact I09 of relay 2TH, front contact I I9 of relay ITR, relay IilH, front contact III of relay ITR, front contact H2 of relay ZTR, and front point of contact II3 of relay HP to terminal C of the same battery.

When relay IOH is energized in the normal direction and relay IOJ is deenergized, alternator IilA is deenergized and relay IBHP is energized by a circuit which passes from terminal B through back point of contact H4 of relay IilJ, front contact I15 and normal polar contact II6-I II both of relay I BE, and relay IEHP to terminal C.

When relay IDHP is energized, the line circuit to the rear is supplied over an easily traced circuit with direct current only of normal polarity.

The slow-releasing characteristic of the relays HP prevents tumble-down of signal control circuits to the rear during pole-changing periods in a manner similar to that described for the relays HP shown in Figs. 1A, 1B, and 1C.

To sum up for the signaling system illustrated in Figs. 2A and 23, each signal is controlled by a polarized direct current line relay and by a neutral direct current line relay. The polarized relay is directly connected to a two-wire line circuit and the neutral relay is connected to the line circuit through an asymmetric unit and a transformer. The line circuit is governed by each of the associated track relays and by the polarized and neutral relays for the signal next in advance.

When both line relays are deenergized, the associated signal will indicate stop and the line circuit to the rear will be supplied with direct current only of reverse polarity. When the polarized relay alone is energized in the reverse direction, the associated signal will indicate approach next signal prepared to stop and the line circuit to the rear will be supplied with alternating current energy simultaneously with direct current of reverse polarity. When the polarized relay is energized in the reverse direction and the neutral relay also is energized, the associated signal will indicate approach next signal at medium speed and the line circuit to the rear will be supplied with direct current only of normal polarity. When the polarized relay only is energized in the normal direction, the associated signal will indicate proceed at normal speed, and the line circuit to the rear will be supplied with direct current only of normal polarity.

Referring now to Fig. 3, the reference characters BX and CX designate the terminals of a source of alternating current such, for example, as any convenient commercial source, which may be substituted at each signal for the alternator A.

As here shown, this source of alternating current is utilized for charging the battery 9 through a rectifier QA and is also utilized to supply alternating current to the primary winding IIB of transformer NA, the secondary winding II9 of which is connected in series with the battery 9 and the line circuit to the rear when relay HP is deenergized. The circuit for supplying energy to primary winding IIB of transformer NA may be traced from terminal BK through back contact 91 of relay J, front contact 98 of relay H, and reverse polar contact 99I00 of relay H, and primary winding M8 to terminal CX. That is, alternating current energy is supplied simultaneously with direct current energy to the line circuit for the section next in rear in a manner similar to that described for the apparatus shown at signal I2 in Figs. 2A and 2B. In other words, when relay H is energized in the reverse direction and relay J is deenergized so that the associated signal will indicate approach next signal prepared to stop, the line circuit to the rear will be supplied with alternating current simultaneously with direct current of reverse polarity so that the signal controlled by that line circuit will indicate approach next signal at medium speed.

The circuits for the control of the signal lamps the relay HP are identical in all respects to those shown and described for the apparatus shown in 2A and 2B.

Referring next to Fig. 4, the circuits for the control of the signal lamps and the relay HP, by the relays H and J, are identical in all respects to those shown in Figs. 2A and 2B.

As here shown, the terminals BX and CK of the commercial source of alternating current are connected to the rectifier QA for charging the battery 9 and also are connected to an alternating current power-off relay P0.

The relay PO, when energized, is effective for connecting the primary winding IQ of transformer N to the terminals BX and GK and, when deenergized, is eifective for connecting the primarywinding I9 to the alternator A. That is, when the commercial source of alternating current is prescut, the alternating current energy required by the line circuit to the rear is supplied from that source and, when the commercial source is absent, the alternating current energy required by the line circuit to the rear is supplied by the alternator A. It is. of course, apparent that the secondary winding 20 of transformer N is connected in series with the line circuit to the rear when the relay HP is deenergized in a manner identical to that described for the transformer N shown in Figs. 2A and 2B.

front contact I2I and reverse polar contact I22---" I23 both of relay H, front point of contact I24 of relay PO, primary winding I 9, and front point of contact I25 of relay PO to terminal CX. The circult for the control of alternator A may be traced from terminal B through back contact 91 of relay J, front contact 98 and reverse polar contact '99-I DI] both of relay H, back contact I26 of relay PO, and winding 24 of alternator 'A to terminal C. It is obvious that, when alternator A is operating a'ndback points of contacts I24andI25 ofrelay P0 are closed, primary winding'IS of transformer N will be alternately energized in one direction and then in the other so that alternat- .ing current will be induced in secondary winding 29,

Referring next to Fig. 5, the signal lamps and the relay HP are controlled by the relays H and J in a manner identical to that shown'and described for the apparatus shown in Figs. 2A :and 2B.

As here shown, the terminals BX and CX of the commercial source of alternating current are connected to the rectifier QA for charging the battery 9 and are connected to the power-01f relay PO.

When relay PO is energized so that the front points of its contacts I24 and I25 are closed, secondary winding H9 or transformer NA supplies the alternating current required by the line to the rear; and when relay PO is deenergized so that the back points of its contacts I24 and I25 are closed, secondary winding 20 of transformer N supplies the alternating current required by the line circuit to the rear. HP is deenergized, either secondary winding H9 of transformer NA or secondary winding 2d of transformer N is connected in series with the line circuit in the rear depending upon whether relay PO is energized or deenergized, respectively.

Primary winding II8 of transformer NA may be supply alternating current to primary winding IQ of transformer N over a circuit which includes back contact 9'! of relay J, and front contact 98' and reverse polar contact 99I03 both of relay H as well as back contact I26 of relay P0.

'In other words, when relay H is energized in the reverse direction and relay J is deenergized so that relay HP is deenergized, the line circuit for the section next in rear will be supplied with direct current of reverse polarity from battery 9 and with alternating current from the commercial source, or from the alternator A in the event of failure of the commercial source.

Although the modifications shown in Figs. 3, 4, and 5 are shown applied to one signal only, it is understood that the circuits and apparatus at any or all signals shown in Figs. 2A and 2B may be modified in a similar manner if desired. Furthermore, the signals shown in Figs. 1A, 1B, and 1C, also, may be controlled by alternating current energy from a commercial source or from an alternator in a manner similar to that shown and described in Figs. 3, 4,, and 5, if desired.

Referring now to Fig. 6, I have herein shown one signal and associated apparatus which, when connected in; a system, will function to provide That is, when relay to three-block, four-indication, signaling in a manner similar to that described for the apparatus illustrated in Figs. 2A and 2B. The principal difference is in the type of signal utilized and in the manner in which the signal is controlled by the relays H and J.

As here shown, the signal includes an upper indication unit HA and a lower indication unit LA. The unit UA is the well-known semaphore arm capable of assuming a horizontal or stop position, a or caution position and a vertical or proceed position. The unit LA comprises a yellow lamp Y.

Associated with the semaphore arm UA is a lamp E which, when lighted, provides the usual and. well-known supplementary color light indications corresponding to the positions of the semaphore arm.

For controlling the lamp E and the lamp Y, a normally energized approach lighting relay ER is connected in series with the line circuit for the section next in rear. That is, when such rear section becomes occupied so that relay ER becomes released to close its back contact I27, lamp E will be then energized and lamp Y will be energized provided its control circuit, to be traced later, is then closed.

It will be noted that a resistor I34 is connected around the relay ER. This resistor is provided to bypass the greater portion of the alternating current supplied to the line circuit in the rear since the impedance of the relay ER usually will be of such value as to retard appreciably the flow of alternating current. If desired, a condenser may be utilized for this purpose instead of a resistor.

Operably connected to semaphore arm UA are contacts I28 and I29 as well as contact I30. Contact I28 is in engagement with contact I3I at all times except when the semaphore arm is in the proceed position. Contact I29 is in engagement with contact I32 when the semaphore arm is in its caution position or in its proceed position or at any point between these two positions. Contact I39 is in engagement with contact I33 when the semaphore arm is in the position (above' horizontal) or is in the proceed position or at any point between these positions.

The signal is provided with an operating battery, the terminals of which are designated by the reference characters B0 and CO, and with a line battery 9L, the terminals of which are designated by the reference characters BL and CL.

The usual alternator A and transformer N are provided for supplying alternating current, and the usual repeating relay HP is provided for controlling the currents supplied to the line circuit in the rear.

The relay H is connected to its line circuit by signal contact I28I3I so that when the semaphore arm is in the proceed position the relay H becomes deenergized. When the relay H is deenergized, the semaphore arm receives its energy directly from the line circuit over back contacts of the relay H. This feature provides for unusually low current consumption since the only current necessary, when the signal is in the normal proceed position, is the current required to hold the semaphore arm in that position and the current required to energize the relay HP. The holding current required by the semaphore arm and by the relay HP is relatively small so that the cost of current for my system is unusually low and results in an appreciable saving, particularly when the current is supplied by primary batteries.

The relay J is connected to secondary winding 59 of transformer M through the usual asymmetric unit Q, and the primary 58 of transformer M is connected to the line circuit through a resistor D. The resistor D performs the same function as the condenser F in the preceding figures, that is, it limits the flow of direct current in the primary winding 58. If the Value of the resistance of primary winding 58 is sufiiciently high, the resistors D and condensers F may be dispensed with as the transformer M will prevent the energization of relay J by direct current in the line circuit.

When the forward section is occupied so that the line circuit for that section is opened, the semaphore arm UA will become deenergized and will assume its horizontal position to indicate top When the semaphore arm is in its horizontal position, relay HP will become deenergized and alternator A will remain deenergized so that the line circuit to the rear will be supplied, over back points of contacts I46 and I47 of relay HP, with direct current only of reverse polarity from the line battery 9L.

When relay H alone is energized in the reverse direction, a caution circuit for semaphore arm UA will be closed over a path which passes from terminal BO through front point of contact I35 of relay H, semaphore arm UA, and front point of contact I35 of relay H to terminal CO. The signal will then display its semaphore arm UA in the caution position to indicate approach next signal prepared to stop.

With the signal displaying this indication and with relay H only energized in the reverse direction, relay HP will remain deenergized but alternator A will become energized over a circuit which passes from terminal BO through signal contact I29-I32, back point of contact I31 of relay J, front contact I38 and reverse polar contact I39I40 both of relay H, and operating winding 24 of alternator A to terminal CO.

When relay HP is deenergized and alternator A is operating to supply alternating current to transformer N, the line circuit to the rear will be supplied with alternating current simultaneously with direct current of reverse polarity over back points of contacts I46 and I4! of relay HP.

When relay H is energized in the reverse direction and relay J also is energized, the caution circuit for semaphore arm UA will remain closed and a circuit for lamp Y, which includes front point of contact I35 and reverse polar contact l4I-I42, both of relay H, as well as front contact I43 of relay J, will be established so that the signal will be in condition, when relay ER becomes deenergized, to display a yellow light below the semaphore arm in the caution position to indicate approach next signal at medium speed.

With the signal in this condition and with relay J energized, the alternator A will become deenergized because of the picking up of contact I31 of relay J, and the relay HP will become energized so that the line circuit to the rear will be supplied with direct current only in the normal direction over front points of contacts I46 and I47 of relay HP. The circuit for energizing relay HP includes terminal BO, signal contact I29-I32, front contact I31 of relay J, and winding of relay HP.

When relay H is energized in the normal direction and relay J is deenergized, the caution circuit for the semaphore arm will remain closed and a proceed circuit for the semaphore arm will be closed over a path which passes from terminal BO through front point of contact I35 of relay H, normal polar contact I4IIM of relay H, semaphore arm UA, and front point of contact I36 of relay H to terminal CO, so that the semaphore arm UA will assume its vertical position to indicate proceed at normal speed.

When the semaphore arm UA attains its vertical position, contact I28I3I will become opened so that relay H will become deenergized. When relay H is deenergized, the caution and proceed circuits for semaphore arm UA will be connected directly to the line circuit over back points of contacts I35 and I36 of relay H so that the semaphore arm will be maintained in the proceed position.

The relay HP will be maintained in its energized condition when the relay H is energized in the normal direction and the relay J is deenergized, provided signal contact I29-I32 is then closed, by a circuit which passes from terminal BO through signal contact I29-I32, back point of contact I31 of relay J, front contact I38 and normal polar contact I39-I l5 both of relay H, and relay HP to terminal CO.

When the semaphore arm is in the vertical position, a second circuit for relay HP, including signal contact HEB-I33, will be closed so that this relay will be maintained in the energized condition to supply direct current only in the normal direction to the line circuit in rear over front points of contacts I46 and M1 of relay HP.

The relay HP is provided with a slow-release characteristic so that, during pole-changing periods, the energization of the line circuit to the rear is not disturbed.

Summing up for the signal and associated apparatus shown in Fig. 6, it will be seen that the line circuit for the section first in rear of an occupied section is supplied with direct current energy only of reverse polarity to cause the signal for such. rear section to indicate prepare to stop at next signal; that the line circuit for the section second in rear of an occupied section will be supplied with alternating current simultaneously with direct current of reverse polarity to cause the signal controlled by such second section in rear to indicate "approach next signal at medium speed; and that the line circuit for the section third in rear of an occupied section and each successive section will be supplied with direct current only of normal polarity to cause the signals controlled by such rear line circuits to indicate proceed at normal speed.

Referring next to Fig. '7, the signal and associated apparatus shown therein will function in. a manner similar to that described for the apparatus shown in Fig. 6, the principal difference being in the manner in which the currents for the line circuit for the section next in rear are controlled.

In addition to signal contact I28I3I, the semaphore arm UA operates pole-changing contacts I53, I53, IEI, and I52. Contacts I49 and I53 are in engagement with contacts I53 and I54, respectively, when the semaphore arm is at any point between the 43 position (above horizontal) and the vertical position, and are in engagement with contacts I55 and I56, respectively, when the semaphore arm is at any point below the 43 position. Contacts I5] and I52 are in engagement with contacts I51 and I58, respectively, when the semaphore arm is at any point between the 60 position (above horizontal) and the vertical position, and are in engagement with contacts I59 and I60, respectively, when the semaphore arm is at any point below the 60 position.

The signal lamps E and Y are controlled by back contact I21 of approach lighting relay ER which is connected in series with the line circuit for the section next in rear.

For supplying the alternating current required for the rear line circuit, the transformer NA is provided having its primary winding H8 connected to terminals BX and CK of any convenient source of alternating current and having its secondary winding H9 connected in series with the line circuit to the rear when that line circuit is to be supplied with alternating current.

When the line circuit is opened, the semaphore arm UA will assume its horizontal position to indicate stop.

When the relay H only is energized in the reverse direction, semaphore arm UA will be energized over a caution circuit which passes from terminal BO through front point of contact Iii! of relay H, semaphore arm UA, and front point of contact I62 of relay H to terminal so that the signal will display the semaphore arm in the caution position to indicate approach next signal prepared to stop.

When relay H is. energized in the reverse direction and relay .J also is energized, the caution circuit for semaphore arm. UA will remain closed and a circuit including front contact I53 of relay J and front contact I64 of relay H will be established for lamp Y so that, when relay ER becomes deenergized, the signal will display a yellow light below the semaphore arm in the caution position to indicate approach next signal at medium speed.

When the relay H only is energized in the normal direction; the caution circuit will remain closed and a proceed circuit for the semaphore arm will be closed over a. path which passes from terminal BO through front point of contact IIiI of relay H, normal polar contact I65i55 of relay H, semaphore arm UA, and front point of contact I62 of relay H to terminal CO, so that the signal will display the semaphore arm in the proceed position to indicate proceed at normal speed.

When the semaphore arm is in the proceed position, signal contact I28-I3I will become opened so that relay H will become deenergized to connect, directly to the line circuit over back points of contacts IBI and I62, the caution and proceed circuits for semaphore arm UA.

When the semaphore arm is in the stop condition, the line circuit to the rear will be supplied with direct current only of reverse polarity over a circuit which includes pole-changing contacts LEG-456 and I49I55.

When the semaphore arm is in the caution position and relay J is deenergized, the line circuit to the rear will be supplied with alternating current simultaneously with direct current of reverse polarity over a circuit which includes back points of contacts I6? and IE8 of relay J, and signal contacts III59 and i52IIid as well as signal contacts iii-I53 and I5EI54.

When the semaphore arm is in the caution position and relay J is energized, the line circuit to the rear will be supplied with direct current only of normal polarity over a circuit which includes front. points of contacts I61 and I68 of relay J, and signal contacts II-I59 and I52I60 as well as signal contacts I49-I53 and I50I54.

When the semaphore arm is in the proceed position, the line circuit to the rear is supplied with direct current only of normal polarity over a circuit which includes signal contacts I5II51 and I52I58 as well as signal contacts I49-I53 and I50-I54.

It will be noted that with this arrangement for controlling the supply of current to the line circuit in the rear, the necessity for the pole-changing relay HP is dispensed with.

Referring next to Fig. 8, the signal and associated apparatus is substantially the same as shown in Fig. 6 except in the manner in which the direct current and alternating current is supplied to the line circuit in the rear.

In addition to signal contact I28-I3I, the semaphore arm UA is provided with signal contacts I10, I1I, I12, and I13. Contact I is in engagement with contact I14 when the semaphore arm is in the 43 position (above horizontal) or in the 89 position or at any point between these two positions. Similarly, contact "I is in engagement with contact I when the semaphore arm is at any point between the 43 position and the 89 position. Contacts I12 and I13 are in engagement with contacts I18 and I11, respectively, when the semaphore arm is in the 55 position or in the proceed position or at any point between these two positions, and are in engagement with contacts I18 and I19, respectively, when the semaphore arm is at any point below the 55 position.

Then the line circuit is opened, semaphore arm UA will assume the horizontal position to indicate stop.

When the relay H only is energized in the re- "verse direction, semaphore arm UA will be energized over a caution circuit which passes from terminal BO through front point of. contact I80 of relay H, semaphore arm UA, and front point of contact I8I of relay H to terminal CO, so that the signal will display the semaphore arm in the caution position.

When the relay H is energized in the reverse direction and the relay J also is energized, the caution circuit for semaphore arm UA will remain closed and relay HP will be energized, providing semaphore arm UA is in the caution position, over a circuit which passes from. terminal BO over front point of contact I80 of relay H, reverse polar contact I82-I83 of relay H, front point of contact I84 of relay J, signal contact I10-I14, front contact I85 of relay H, and relay HP to terminal CO.

When relay J is energized and relay HP also is energized, a circuit, including front point of contact I86 of relay HP and front contact I81 of relay J, will be established for lamp Y so that when relay ER is released, the signal will display a yellow lamp below the semaphore arm in the caution position.

When the relay H only is energized in the normal direction, the caution circuit for the semaphore arm will remain closed and a proceed circuit will be closed over a path which passes from terminal BO through front point of contact I80 of relay H, normal polar contact I82I88, semaphore arm UA, and front point of contact I 8I of relay H to terminal CO so that the semaphore arm will assume the proceed position.

When the semaphore arm is in the proceed position, signal contact |28I3I will become opened so that relay H will become deenergized to connect semaphore arm UA to the line circuit over back contacts I80 and I 8| of relay H.

When the semaphore arm is in the stop position, relay HP will become deenergized because of release of contact I85 of relay H so that the line circuit to the rear will be supplied with direct current only of reverse polarity from line battery 9L, over a circuit which includes signal contacts I12I18 and I13I19 as well as back points of contacts I89 and I90 of relay 1-D? and relay ER in multiple with resistor I34.

When the semaphore arm is in the caution position and relay J is deenergized, relay HP will remain deenergized and the alternator A will be energized over a circuit which passes from terminal 130 through back point of contact I86 of relay HP, signal contact I1II15, and winding 24 of alternator A to terminal CO, so that the line circuit to the rear will be supplied with alternating current simultaneously with direct current of reverse polarity over a circuit which includes relay ER and resistor I34 in multiple, and signal contacts I12I18 and I13I19, as well as back points of contacts I89 and I90 of relay HP.

When the semaphore arm is in the caution position and the relay J is energized, relay HP will be. energized, provided relay H is then energized in the reverse direction, over the pickup circuit for relay HP already traced so that alternator A will become deenergized and the line circuit to the rear will be supplied with direct current only in the normal direction over a circuit which includes relay ER and resistor I34 in multiple as well as front points of. contacts I89 and I90 of relay HP.

When the semaphore arm is in the proceed position, relays H and HP become deenergized and the line circuit to the rear is supplied with direct current only of normal polarity over a circuit which includes relay ER and resistor I34 in multiple and signal contacts I12 I16 and I13I11.

Referring now to Fig. 9, I have herein shown how one alternator A may be controlled for supplying alternating current for the signal systems for each of two parallel tracks.

As here shown, each track is provided with a signal and associated apparatus which, except for the manner in which alternating current is supplied to the line circuit in the rear, is identical in all respects to the signal and associated apparatus shown in. Fig. 8.

The signal for the lower track is provided with signal contact I9II92 which is closed at the same time as signal contact I1I-I15, that is, when the semaphore arm UA is in the 43 position (above horizontal) or in the 89 position or at any point between these two positions.

Similarly, the signal for the upper track is provided with contacts l93-I94 and I95-I98 each of. which is closed when the semaphore arm for that signal is in the 43 or 89 positions or at any point between these positions.

The alternator A is provided with two easily traced energizing circuits one of which includes signal contact I9II9Z and the other of which includes contact I95-I96, so that the alternator will operate when either semaphore arm is in the caution position.

When the alternator is operating, alternating current will be supplied to primary winding I 9 of transformer N, the secondary winding 20 of which is connected, by signal contact I1I-I 15 of the signal for the lower track and back contact I91 of relay 1-11 for that signal, to the primary winding H8 of transformer NA for that signal; and by signal contact l93l94 of the signal for the upper track and back contact N8 of relay HP for that signal, to the primary winding I N3 of transformer NA for that signal.

Since the secondary windings I IQ of the transformers NA are connected in the usual manner with the line circuits in rear of their respective signals, it will be obvious how alternating current is supplied to such line circuits from the single alternator A.

Although, in Fig. 9, I have shown only one signal and associated apparatus for each track, it will be understood that each signal, when connected in a system, will function to provide fourindication, three-block signaling for the respective tracks.

Although I have herein shown and described only a few forms of apparatus embodying my invention, it is understood that Various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A railway signal system comp-rising a plurality of successive sections of railway track each having a pair of conductors governed by traffic conditions in said section, means efiective when one section is occupied to supply the conductors for the section first in rear of such occupied section with current of one character, means then effective to supply the conductors for the section second in rear of such occupied section with current of another character simultaneously with current of said one character, means then effective to supply the conductors for the section third in rear of such occupied section with current of still a different character, and signaling means for each section governed by the associated conductors and selectively responsive to the character and number of the currents with which such conductors are supplied.

2. A railway signal system comprising a plurality of successive sections of railway track each having a pair of conductors governed by trafiic conditions in said section, means effective when one section is occupied to supply the conductors for the section first in rear of such occupied section with current of one character, means then effective to supply the conductors for the. section second in rear of such occupied section with current of another character simultaneously with current of said one character, means then effective to supply the conductors for the section third in rear of such occupied section with current of still a different character, means then effective to supply the conductors for the fourth section in rear of such occupied, section with current of said other character simultaneously with current of said different character, and signaling means for each section governed by the associated conductors and selectively responsive to the character and number of the currents with which such conductors are supplied.

3. A railway signal system comprising; a first, a second, a third, and a fourth track section over which traffic normally progresses in the order named, a pair of conductors for each section governed by trafiic conditions in such section, a polarized direct current relay for each section receiving energy from the associated conductors, a neutral direct current relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated polarized and neutral relays, means effective when the fourth section is occupied to supply the conductors for the third section with direct current only of reverse polarity, means then effective to supply the conductors for the second section with alternating current simultaneously with direct current of reverse polarity, and means then effective to supply the conductors for the first section with direct current only of normal polarity.

4. A railway signal system comprising a first, a second, a third, a fourth, and a fifth track section over which trafiic normally progresses in the order named, a pair of conductors for each section governed by traffic conditions in said section, a polarized direct current relay for each section connected to the associated conductors, a neutral direct current relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed jointly by the associated polarized and neutral relays, means efiective when the fifth section is occupied to supply the con-ductors for the fourth section with direct current only of reverse polarity, means then effective to supply the conductors for the third section with alternating current simultaneously with direct current of reverse polarity, means then efiective to supply the conductors for the second section with direct current only of normal polarity, and means then effective to supply the conductors for the first section with alternating current simultaneously with direct current of normal polarity.

5. In combination, a plurality of successive. sections of railway track, a pair of conductors for each section governed by trafiic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a neutral direct current relay for each section, means including a transformer and a rectifier as well as a condenser for connecting each neutral relay to the associated conductors, means for each section for supplying direct current only of reverse polarity to the conductors for the section next in rear when both the polarized relay and the neutral relay are deenergized, means for each section for supplying alternating current simultaneously with direct current of reverse polarity to such conductors in rear when the polarized relay is energized reverse and the neutral relay is deenergized, means for each section for supplying direct current only of normal polarity to such conductors next in rear when the polarized relay is energized reverse and the neutral relay is energized, means for each section for supplying alternating current simultaneously with direct current of normal polarity to such conductors next in rear when said polarized relay is energized normal and said neutral relay is deenergized, means for each section forsupplying alternating current simultaneously with direct current of normal polarity to such conductors next in rear when said polarized relay is energized normal and said neutral relay is energized, and a signal for each section governed by the associated polarized and neutral relays.

6. In combination, a plurality of successive sections of railway track, a pair of conductors for each section governed by traflic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a neutral direct current relay also receiving energy from the associated conductors through an asymmetric unit, means for each section for supplying direct current only of reverse polarity to the conductors for the section next in rear when both the polarized and the neutral relays are deenergized, means for each section for supplying alternating current simultaneously with direct current of reverse polarity to such conductors next in rear when the polarized relay is energized reverse and the neutral relay is deenergized, means for each section for supplying direct current only of normal polarity to such conductors next in rear when the neutral relay is energized, means for each section for supplying direct current only of normal polarity to such conductors next in rear when the polarized relay is energized normal and the neutral relay is deenergized, and a signal for each section governed jointly by the associated polarized and neutral relays.

7. In combination, a railway track divided into sections, a pair of conductors for each section governed by traffic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized respectively, and means for each section for also ,m' supplying such conductors for the section next in rear with alternating current effective when said slow-acting relay is deenergized provided the associated polarized relay is then energized in the reverse direction and the associated neutral relay is then deenergized.

8. In combination, a railway track divided into sections, a pair of conductors for each section governed by trafiic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section, a circuit for said slow-acting relay including a front contact of the associated neutral relay, another circuit for said slow-acting relay including a back contact of said neutral relay and a front contact of the associated polarized relay as well as a normal polar contact of said polarized relay, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or of reverse polarity according as said slow-acting relay is energized or deenergized respectively, and means for each section for also supplying such conductors for the section next in rear with alternating current effective when the associated slow-acting relay is deenergized provided the associated polarized relay is then energized in the reverse direction and the associated neutral relay is then deenergized.

9. In combination, a railway track divided into sections, a pair of conductors for each section governed by traflic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized respectively, and means for each section for also supplying such conductors for the section next in rear with alternating current effective when the associated polarized relay is energized in the normal direction or when the associated neutral relay is deenergized provided the polarized relay is then energized in the reverse direction.

10. In combination, a railway track divided into sections, a pair of conductors for each section governed by traific conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section Which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized respectively, and means for each section including a tuned reed alternator for also supplying such conductors for the section next in rear with alternating current effective when the associated polarized relay is energized in the normal direction or when the associated neutral relay is deenergized provided the polarized relay is then energized in the reverse direction.

11. In combination, a railway track divided into sections, a pair of conductors for each section governed by traffic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slowacting relay is energized or deenergized respectively, and means for each section including a tuned reed alternator for also supplying such conductors for the section next in rear with alternating current effective when the associated slow-acting relay is deenergized provided the associated polarized relay is then energized in the reverse direction and the associated neutral relay is then deenergized.

12. In combination, a railway track divided into sections, a pair of conductors for each section governed by trafiic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in, rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized respectively, a transformer for each section having a primary winding and a secondary winding, means for each section including a back contact of the associated slow-acting relay for connecting the secondary winding of the associated transformer in series with such conductors for the section next in rear, and means for each sec tion for supplying the primary winding of the associated transformer with alternating current eifective when the associated polarized relay is energized in the reverse direction provided the associated neutral relay is then deenergized.

13. In combination, a railway track divided into sections, a pair of conductors for each section governed by trafiic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized respectively, a transformer for each section having a primary winding and a secondary winding, means for each section including a back contact of the associated slow-acting relay for connecting the secondary winding of the associated transformer in series with such conductors for the section next in rear, an alternator for each section having its output terminals connected to the primary winding of the associated transformer, and a circuit for energizing each alternator including a back contact of the associated neutral relay and a front contact as well as a reverse polar contact of the associate-d polarized relay.

14. In combination, a railway track divided into sections, a pair of conductors for each section governed by traflic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direction, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized respectively, an alternator for each section, a transformer for each section having its primary connected to the output terminals of the associated alternator and its secondary winding connected in series with one of the conductors for the section next in rear, a circuit for energizing each alternator including a back contact of the associated neutral relay and a front contact as well as a reverse polar contact of the associated polarized relay and another circuit for energizing each alternator including a front contact and a normal polar contact of the associated polarized relay.

15. In combination, a railway track divided into sections, a pair of conductors for each section governed by trafiic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direc tion, means for each section for supplying the conductors for the section next in rear with direct current of normal polarity or with direct current of reverse polarity according as the associated slow-acting relay is energized or deenergized re spectively, a transformer for each section having a primary winding and a secondary winding, a first source of alternating current for each section, a second source of alternating current for each section, a transfer relay for each section connected to the first associated source of alternating current, means for each section including a back contact of the associated slow-acting relay for connecting the secondary winding of the associated transformer to the conductors for the section next in rear, and means for each section for connecting the primary winding of the associated transformer to said first associated source of alternating current or to said second associated source of alternating current according as said transfer relay is energized or deenergized respectively.

16. In combination, a railway track divided into sections, a pair of conductors for each section governed by trafiic conditions in said section, a direct current polarized relay for each section receiving energy from the associated conductors, a direct current neutral relay for each section receiving energy from the associated conductors through an asymmetric unit, a signal for each section governed by the associated neutral and polarized relays, a slow-acting relay for each section which is energized when the associated neutral relay is energized or when the associated neutral relay is deenergized and the associated polarized relay is energized in the normal direc- 

